Chapter 18: Air Pollution (Alex) Flashcards
The thin blanket of gases surrounding the Earth
The atmosphere
The atmospheres’ two innermost layers
The troposphere and the stratosphere
The number of gas molecules per unit of air volume
Density
Why does the density vary throughout the atmosphere?
Gravity pulls gas molecules towards the Earth’s surface. Therefore the lower layers of the atmosphere have more gases than the upper layers and are denser.
The force per unit area of a column of air
Atmospheric pressure
Why are density and atmospheric pressure important?
They play major roles in weather
In which atmospheric layer is 75%-80% of the Earth’s air mass found in?
The troposphere which is the layer closest to the Earth
How far above the equator does the troposphere extend and how far above the poles?
17 km and 6km
What two gases make up 99% of the air?
Nitrogen (78%) and oxygen (21%)
Rising and falling air currents, winds, and concentrations of CO2 and other greenhouse gases in the troposphere play a major role in the planet’s short term ________ and long term _______.
Weather and climate
What is the average weather in a given area called?
Climate
What is the second layer of the atmosphere?
The stratosphere
Between what elevations is the stratosphere?
17 km and 48 km
In what layer is much of the atmosphere’s small amount of ozone found in what is called the ozone layer, and at what elevations is it found?
The stratosphere and between 17 km and 26 km
How is most stratospheric ozone produced?
When some of the oxygen molecules in this layer interact with UV radiation emitted by the sun
What percent of the sun’s harmful UV radiation is prevented from reaching Earth’s surface by the ozone layer?
95%
What is the presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, or human-made materials, or to alter climate called?
Air pollution
Almost any chemical in the atmosphere can become a pollutant if?
It occurs in a high enough concentration
What are some natural sources of air pollutants?
Wind-blown dust, pollutants from wildfires and volcanic eruptions, and volatile organic chemicals released by some plants.
Where do most human inputs of outdoor air pollutants occur?
In industrialized and urban areas where people, cars, and factories are concentrated
How are most human-made air pollutants produced?
By the burning of fossil fuels in power plants, industrial facilities, and motor vehicles.
Chemicals or substances emitted directly into the air from natural processes and human activities at high enough concentrations to cause harm.
Primary pollutants
Pollutants formed by the reactions of primary pollutants.
Secondary pollutants
According to the WHO, how many people live in urban areas where outdoor air is unhealthy to breathe?
1.1 billion
What is a colorless, odorless, and highly toxic gas that forms during the incomplete combustion of carbon-containing materials?
Carbon monoxide (CO)
What are the major sources of carbon monoxide?
Motor vehicle exhaust, burning of fossil fuels and grasslands, smokestacks of fossil fuel-burning power plants and industries, tobacco smoke, and open fires and inefficient stoves used for cooking.
What is a colorless, odorless gas that only 93% percent of it in the atmosphere is from its natural cycle?
Carbon dioxide (CO2)
What are the major sources of carbon dioxide?
The burning of fossil fuels and the clearing of CO2-absorbing forests and grasslands
What is a colorless gas that forms when nitrogen and oxygen gas react under high-combustion temperatures in automobile engines and coal-burning power plants and industries?
Nitric oxide (NO)
What component of the nitrogen cycle can also produce NO?
Lightning and certain bacteria in the soil
In the air, NO reacts with oxygen to form what reddish-brown gas?
Nitrogen dioxide (NO2)
Collectively, NO and NO2 are what?
Nitrogen oxides (NOx)
Some of the NO2 reacts with water vapor in the air to form what components of acid deposition?
Nitric acid (HNO3) and nitrate salts (NO3-)
Both NO and NO2 play a role in the formation of what mixture of chemicals formed under the influence of sunlight in cities with heavy traffic?
Photochemical smog
What is a greenhouse gas emitted from fertilizers and animal wastes, and is produced by the burning of fossil fuels?
Nitrous oxide (N20)
What is a colorless gas with an irritating odor with about 1/3 of it in the atmosphere coming from its natural cycle, and where do the other 2/3 come from?
Sulfur dioxide (SO2), human sources, mostly combustion of sulfur-containing coal in power and industrial plants.
In the atmosphere, SO2 can be converted to ________, which consist of microscopic suspended droplets of sulfuric acid (H2SO4) and suspended particles of sulfate (SO4^2-) salts that return to the Earth as a component of acid deposition.
Aerosols
What is a variety of solid particles and liquid droplets that are small enough and light enough to remain suspended in the air for long periods called?
Suspended particulate matter (SPM)
About ___ of SPM in the outdoor air comes from natural sources such as dust, wildfires, and sea salt with the other ___ percent coming from human sources, including coal-burning power and industrial plants, motor vehicles, and road construction.
62%, 38%
What is a colorless and highly reactive gas that is a major ingredient of photochemical smog?
Ozone (O3)
What problems does excess ozone in the troposphere cause?
Coughing and breathing problems, aggravation of lung and heart diseases, reduce resistance to colds and pneumonia and irritate the eyes, nose, and throat. It can also damage plants, rubber in tires, fabrics, and paints.
Why is ozone in the stratosphere good?
It protects us from harmful UV radiation.
What are organic compounds that exist as gases in the atmosphere or as gases that evaporate from sources in Earth into the atmosphere called? Some examples are hydrocarbons emitted by the leaves of many plants and methane.
Volatile organics compounds (VOCs)
What is industrial smog composed of?
An unhealthy mix of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles in outside air.
